Pipe joint



Nov. 8, 1966 w. H. WEST 3,284,107

PIPE JOINT Filed Aug. 13, 1965 INVENTOR. Wa/I er H Wes 7 United States Patent 3,284,107 PIPE JOINT Walter H. West, Bay City, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed Aug. 13, 1965, Ser. No. 479,386 2 Claims. (Cl. 285-55) This invention relates to an improved pipe joint and more particularly relates to an improved pipe oint for synthetic resinous thermoplastic lined pipes.

Considerable difliculty has been encountered in the oming of sections of rigid pipe lines with synthetic resinous thermoplastic materials wherein the pipe or outer acket of the pipe is provided with a flange having a radially extending face. A portion of the lining material is conformed to the radially extending face and pipe sections terminated in this manner are placed in abutting relationship and held together by means of bolts passing through suitable matching apertures in the flanges. Many synthetic resinous thermoplastic materials exhibit the characteristic of cold flow which, after a time, results in the requirement that the bolts be retightened, or in the absence of such tightening, the joint becomes leaky.

It would be beneficial if there were available an improved pipe joint for thermoplastic resinous lined pipes.

It would be further advantageous if there were available a joint for pipes lined with synthetic resinous thermoplastic materials subject to cold flow which would provide an essentially leak-proof joint which would not require frequent retightening.

F urther, it would be advantageous if there were available a leak-proof joint "for pipes which have a thermoplastic resinous lining subject to cold flow which is easily assembled and disassembled.

These benefits and other advantages in accordance with the present invention are achieved in a joint between adjacent pipe sections, each ofthe pipe sections comprising an outer rigid body and a lining of a synthetic resinous material subject to cold flow, each of the pipe sections having a terminal end to be joined, a flange affixed to the rigid outer layer of the pipe and defining a generally outwardly extending radial surface, the flange defining an annular groove within the outwardly extending surface, means to secure adjacent flanges to each other, a terminal flange of synthetic thermoplastic resinous material integral with the lining and extending along the radially outwardly extending face of the flange, an O-ring of a resilient non-thermoplastic material disposed at least partially within adjacent annular grooves of adjacent flanges, the O-ring being disposed adjacent the outer terminal portion of the synthetic resinous flanges.

These features and other benefits in accordance with the present invention will become more apparent from the -following specification when taken in connection with the drawing wherein:

The figure illustrates a pipe joint in accordance with the present invention generally designated by the reference numeral 10.

The pipe joint comprises in cooperative combination a first pipe section 11 and a second pipe section 11a. The pipe sections or conduits 11 and 11a are substantially identical and identical parts are identified in the drawing by the suffix a afiixed to the appropriate reference numeral. The conduit 11 comprises an outer cylindrical conduit 12 of steel or like rigid material having disposed on the inner surface thereof a synthetic resinous thermoplastic lining 13. The conduit 11 has a terminal end 14. A flange 16 is aflixed to the rigid portion of the conduit 12. The flange 16 defines a generally radially outwardly extending surface 17. The flange 16 also defines within the surface 17 a generally annular recess 18 3,284,107 Patented Nov. 8, 1 966 adapted to receive an O-ring 19. The thermoplastic resinous lining 13 terminates in a thermoplastic terminal flange 21 which conforms generally to the configuration of the surface 17 between the annular grooves 18 and the inner portion of the flange 16. The flange 16 defines a plurality of apertures 23. The apertures 23 are adapted to mate with like apertures 23a in the adjacent flange 16a. A plurality of compression means or bolts 25 are disposed within the apertures 23 and 23a. The bolts 25 comprise a head portion 26, a body portion 27', an externally threaded portion 28 and a nut 29 having mating internal threads, not shown, which serve to draw the flanges 16 and 16a together and subsequently force the thermoplastic resinous flanges 21 and 21a into sealing engagement and compressing the O-ring 19.

When a joint such as the joint 10 is prepared and tightened, the pressure from the inside of the conduit and the compression force exerted by the bolts 25 tend to cause cold flow of the thermoplastic flanges 21, the thermoplastic flanges 21 are drawn together compressing the O-ring and causing the face of opposed flanges 21 to effect a double seal at the joint interface. Any movement of the thermoplastic flanges 21 due to internal pressure within the conduit is effectively halted by the resilient O-ring and as the material is forced against the O-ring, the seal becomes more and more secure as such pressure also appears as compressional force forcing the thermoplastic flanges 21 and 21a against each other and against the surfaces 17 and 1711, respectively.

Steel pipes lined with synthetic resinous materials such as saran (a copolymer of about percent vinylidene chloride and about 15 percent vinyl chloride) exhibit excellent leak-proof joints when conventional rubber O-rings are employed substantially in accordance with the figure.

Similar beneficial results are achieved when materials such as polyethylene, polypropylene, nylon and a polyether composition sold commercially under the trade name of Penton are employed as linings for steel pipes and used in accordance with the present invention.

As is apparent from the foregoing specification, the present invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto-appended claims.

What is claimed is:

1. A pipe joint between adjacent pipe sections, each of the pipe sections comprising an outer rigid body and a lining of a synthetic resinous material subject to cold flow, each of the pipe sections having a terminal end to be joined, a flange aflixed to the rigid outer layer of each pipe section and defining a generally outwardly extending radial surface, each flange having an annular groove within the outwardly extending surface, the grooves be ing of substantially the same radius, means to secure adjacent flanges to each other, a terminal flange of synthetic thermoplastic resinous material integral with the lining in each pipe section and extending along a centrally located generally circular portion of the radially outwardly extending face ofthe afiixed flange, an O- ring of a resilient sealing material disposed in said grooves, the axial depth of each of the grooves being less than the radius of the O-rihg cross-section, the grooves being disposed adjacent the outer terminal portion of the synthetic resinous flanges and within the means to secure adjacent flanges to each other, said securing means drawing said flanges together to compress said O-ring and the terminal flanges to thereby efiect a double seal at said joint interface. 1

22,253 2. The joint of claim 1 whereln the seallng material 22 is rubber. 5 1,328,981 810,400

References Cited by the Examiner 413,142

UNITED STATES PATENTS 1,351,573 8/1920 Hopwood 285336 2,907,103 10/1959 Lewis 28555 3,120,40'1 2/1964 Brown 285-367 10 3,142,499 7/1964 Lang 285-55 FOREIGN PATENTS CARL W. TOMLIN, Primary Examiner.

R. GIANGIORGI, Assistant Examiner. 

1. A PIPE JOINT BETWEEN ADJACENT PIPE SECTIONS, EACH OF THE PIPE SECTIONS COMPRISING AN OUTER RIGID BODY AND A LINING OF A SYNTHETIC RESINOUS MATERIAL SUBJECT TO COLD FLOW, EACH OF THE PIPE SECTIONS HAVING A TERMINAL END TO BE JOINED, A FLANGE AFFIXED TO THE RIGID OUTER LAYER OF EACH PIPE SECTION AND DEFINING A GENERALLY OUTWARDLY EXTENDING RADIAL SURFACE, EACH FLANGE HAVING AN ANNULAR GROOVE WITHIN THE OUTWARDLY EXTENDING SURFACE, THE GROOVES BEING OF SUBSTANTIALLY THE SAME RADIUS, MEANS TO SECURE ADJACENT FLANGES TO EACH OTHER, A TERMINAL FLANGE OF SYNTHETIC THERMOPLASTIC RESINOUS MATERIAL INTERGRAL WITH THE LINING IN EACH PIPE SECTION AND EXTENDING ALONG A CENTRALLY LOCATED GENERALLY CIRCULAR PORTION OF THE RADIALLY OUTWARDLY EXTENDING FACE OF THE AFFIXED FLANGE, AN ORING OF A RESILIENT SEALING MATERIAL DISPOSED IN SAID GROOVES, THE AXIAL DEPTH OF EACH OF THE GROOVES BEING LESS THAN THE RADIUS OF THE O-RING CROSS-SECTION, THE GROOVES BEING DISPOSED ADJACENT THE OUTER TERMINAL PORTION OF THE SYNTHETIC RESINOUS FLANGES AND WITHIN THE MEANS TO SECURE ADJACENT FLANGES TO EACH OTHER, SAID SECURING MEANS DRAWING SAID FLANGES TOGETHER TO COMPRESS SAID O-RING AND THE TERMINAL FLANGES TO THEREBY EFFECT A DOUBLE SEAL AT SAID JOINT INTERFACE. 